1. Field of the Invention
This invention relates to an improved windshield wiper blade assembly and, more particularly, to an improved connection between the primary yoke and the secondary yokes. The invention is also directed to an improved method for molding the secondary yokes using a two-part mold arrangement.
2. Description of the Prior Art
Since the introduction of articulated windshield wiper blades for wiping curved and flat windshields, first disclosed in the J. W. Anderson U.S. Pat. No. 2,596,063, many improvements have been made on various elements of the articulated structure with the view to improving upon the operation of the whole wiper blade assembly. The connections between the primary yokes and the secondary yokes, although functioning very adequately, have, on occasion, given some problems both in assembly and in making noise during use.
The most common form of connection between the primary and secondary yokes is a pin or rivet passing between the downturned legs of the inverted channel shaped primary yoke and between the side walls of the downturned U-shaped channel of the secondary yoke. This form of connection, after some considerable use of the blade, will begin to make noises, such as small clicking noises, whenever the direction of movement of the blade is reversed, i.e. from moving left to moving right or vice versa. Special bushing arrangements have been provided which reduce the extent of the problem but still over a period of time looseness and noise develops.
In another design of the articulated superstructure for a wiper blade, different forms of release mechanisms for the connection between the primary and secondary yoke have been provided. These mechanisms include springs, ears, actuator members and the like to make it possible to separate the primary yoke from the secondary yoke by depressing the actuator thereby releasing the spring and making it possible to move the primary yoke relative to the secondary yoke for disconnecting the primary yoke from the secondary yoke.
Still another popular form of connection between the primary yoke and secondary yoke has been to extend a pair of ears from the primary yoke downwardly beyond the lower edges of the inverted U-shaped channel of the secondary yoke with said ears being bent inwardly to nest in slots formed in the bottom edges of said secondary yokes. Once again, this construction is subject to wear and does create noise when the direction of movement of the blade is reversed as the blade traverses the surface of a windshield.
Also, heretofore, whenever a yoke has been molded, it generally required several die parts and die pins in order to mold the claws on the lower ends thereof. The dies being complicated, are subject to wear and must be constantly upgraded which increases the cost of the molding of the individual parts.